158 S. C. Rafanoharana et al.


TABLE 2 Number and size of forest blocks and total forest area in 2017, and deforestation per year during 2015–2017 in the protected areas of Madagascar (Fig. 1), by IUCN category, and projections of per cent forest loss during 2017–2050 and total forest area in 2050.


IUCN category I


II


III IV V


VI I–VI combined


Number of forest blocks in 2017


2


48 1


26 66 27


170


Size of forest blocks in 20171 (km2)


13.62/868.00 7.09–28.21–16.61


Total forest area in 2017 (km2)


5.37–52.56–422.77 16,319.55 37.45


2.37–20.48–54.38 10,236.33 4.81–9.13–86.34


2,667.44 6,331.56


4.57–21.92–172.27 36,473.94 1Values are medians and quartiles (Q25–median–Q75).


median size of these blocks was 21.92 km2, with an inter- quartile range of 4.57–172.27 km2. With a median area of 37.45 km2, IUCN categories I–III


protected areas were larger than the IUCN categories IV–VI protected areas, whose median areas were 9.13–28.21 km2 (Table 2). The former comprised 47.3% of the whole pro- tected forest area. The annual deforestation rate during 2015–2017 ranged


between no measurable change to a decrease of 13.57% per year (Table 2). It differed significantly depending on IUCN category, with protected areas of IUCN categories IV–VI having higher deforestation rates than those of IUCN category II (Kruskal–Wallis ANOVA without pro- tected areas of categories I and III, removed because of small sample size: H= 19.07,P,0.001,df = 3). Annual deforestation in IUCN category II protected areas differed significantly from those in IUCN categories V and VI (Mann–Whitney U: P#0.01, Bonferroni corrected). IUCN category I protected areas are Betampona and Tsaratanana, and the IUCN category III protected area is Alandraza- Analavelo. Deforestation rate was not related to the size of the forest


blocks within the protected areas (Spearman’s correlation: rs = 0.12,P.0.05,N = 170).


Projecting forest loss to 2050


Assuming constant deforestation rates in all protected areas, the protected forest is projected to decrease by 9,306 km2 during 2017–2050 (c. 25% of the total forest area). The de- crease in IUCN categories I–III protected areas is projected to be 16.88% during 2017–2050, and 21.31–39.16% in the other IUCN categories. In 2017, 68 (40%) of the 170 forest blocks were,10 km2.


Apart from these smallest blocks, the largest number of forest blocks were 160–320 km2 (Fig. 1). By 2050,these figures are projected to have changed to 76 (45%) forest blocks , 10 km2, with the mode projected to be 80–160 km2.


FIG. 2 Occurrence of lemur species in the protected areas of Madagascar as of 2017. The numbers on the x-axis represent the number of protected areas where any given lemur species has been recorded (e.g. 30 species are known from a single protected area and 10 species from two areas).


Oryx, 2024, 58(2), 155–163 © The Author(s), 2023. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605323001175 Perspectives for lemur species


Two lemur species are not known to occur in any protected area. Microcebus boraha is restricted to Île Sainte Marie, an island off the east coast of Madagascar that lacks any protected areas (Reuter et al., 2020). The distribution of Lepilemur grewcockorum falls between Bongolava Reserve, 30 km south-south-east of the reported occurrence of this species, and the Réserve Spéciale Bora, 57 km to the north- east (Louis et al., 2020). The remaining 105 of the 107 recog- nized lemur species are recorded in at least one protected area, although the representation of IUCN categories for protected areas varies widely between species (Supplemen- tary Table 1). Thirty species are known only from a single protected area, and .50% of them occur in no more than four protected areas (Fig. 2). On average, by 2050 the forested area currently inhabited by lemurs is projected to decrease by 19% (Supplementary Table 2).


881.62 37.45


Deforestation per year during 2015–20171 (%)


0.00/1.29


0.04–0.19–0.56 0.02


0.03–0.44–1.41 0.14–0.95–2.74 0.55–1.95–3.18 0.07–0.52–1.96


Projected forest loss during 2017–2050 (%)


0/34.63 15.97 0.76


21.31 39.16 28.73 25.51


Projected total forest area in 2050 (km2)


13.62/564.78 13,712.58 37.16


2,099.10 6,228.18 4,512.67 27,168.10


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